Levees, Liability & Mitigation NHMA Symposium – July 2016 Jim Murphy, PE, CFM AECOM
The Flood Control Infrastructure Has Provided Protection/Reduced Risk to Millions
Risk = f(Hazard, Performance, Consequences) What are the hazards and how likely are they to occur? How will the infrastructure perform in the face of these hazards? Who and what are in harms way? How susceptible to harm are they? How much harm is caused? Risk = Likelihood x Consequences Includes Factors affecting performance of system Factors affecting consequences Any uncertainty Risk reduction actions (May include classification) USACE Levee Safety Program: Focused on People, Risks, and Actions Recognizes Uncertainties
Levees – Not Just an Engineering Challenge “Building a levee is initially an economic decision. A levee may not always eliminate the misery, it may only delay it until that point in time when nature’s forces exceed man’s willingness to invest in greater risk protection.”
Murphy’s Axiom: If you build it they will come and assume that someone else is paying. The Floodplain Management Challenge What happens on the dry side of a levee? Rule # 1. A levee would not be there if it was not meant to protect stuff! Rule # 2. Economics dictates the accumulation of more stuff – barring constraints. Rule # 3. Most of the time levees and floodwalls look REALLY STRONG! Rule # 4. Folks do not like constraints.
USACE Slide courtesy of Pete Rabbon
PRACTICAL EXERCISE Split into 3 Groups: City Mayor & Development Authority City Engineer City Attorney
Area A – Behind certified levee Issues/concerns & mitigation strategy City Mayor & development Authority City Engineer City Attorney
Area B – Behind a non- certified levee Issues/concerns & mitigation strategy City Mayor & development Authority City Engineer City Attorney
Area – No levee (area of potential development?) Issues/concerns & mitigation strategy City Mayor & development Authority City Engineer City Attorney
Thought for the Day Flood Insurance For Property Owners – A certified levee will help reduce risk. What Does a Certified Levee Protect Against? Flood Insurance
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